Influence of Board Spacing on Mitigating Wood Decking Assembly Ignition

As part of recent building code change discussions, it has been suggested that by increasing the spacing of boards, it may be possible to mitigate ignition of wood decking assemblies from wind-driven firebrand showers. An experimental series was undertaken to vary the board spacing from 0 mm (no gaps), 5 mm, and 10 mm, to determine if it was possible to observe reduced ignition propensity of full-scale wood decking assemblies fitted to a reentrant corner wall assembly. In these experiments, three common wood types were used and firebrand showers were directed at the wall/decking assemblies using wind speeds of 8 m/s generated using a realistic-scale wind tunnel. Based on the results of these experiments, it was observed that board spacing significantly influenced ignition propensity of these assemblies. Ignition events were observed for all board spacing considered and in particular, more ignition points were observed for a board spacing of 10 mm.